Various types of intermediate transfer members are known and are described, for example in U.S. Pat. Nos. 3,862,848, 4,684,238, 4,690,539 and 4,531,825.
Belt-type intermediate transfer members for use in electrophotography are known in the art and are described, inter alia, in U.S. Pat. Nos. 3,893,761, 4,684,238 and 4,690,539.
In both liquid and powder toner imaging systems employing intermediate transfer members it is known to heat the toner images on the intermediate transfer member before transfer to the final substrate. In U.S. Pat. No. 4,708,460 a liquid toner image is heated by radiant heat from a heater external to the transfer member in order to evaporate the liquid carrier and to melt the solid toner before transfer. In U.S. Pat. No. 4,518,976 there is described a belt image transfer system, wherein the belt is heated by a heating roller which is provided at the back of the belt during transfer from the belt to the final substrate. In U.S. Pat. No. 4,585,319 a radiant heater in the center of a drum ITM is used to heat the ITM.
The use of intermediate transfer members is well known in the printing art. In offset printing an image formed of a viscous ink is transferred from a drum to a second drum prior to transfer to the final substrate. It has bee recognized that the pressures between the various drums and against the final substrate are important to the quality of the final print. Two types of offset blankets are generally available, consistent with the ink characteristics.
Conventional printing blankets are relatively stiff and have little leeway for packing error. Compressible blankets are made with varying compressibilities, with typical curves shown for example on page 33 of "Web Offset-Press Operating", published by Graphic Arts Technical Foundation, Pittsburgh, Pa., 1984.
The pressures used in offset printing are not generally measured, but it is believed that they are in the general vicinity of 100-150 lb./sq. in. as indicated in the above reference and in U.S. Pat. No. 3,983,287.